Power semiconductor module arrangements often include a base plate within a housing. At least one substrate is arranged on the base plate. A semiconductor arrangement including a plurality of controllable semiconductor elements (e.g., two IGBTs in a half-bridge configuration) is arranged on each of the at least one substrate. Each substrate usually comprises a substrate layer (e.g., a ceramic layer), a first metallization layer deposited on a first side of the substrate layer and a second metallization layer deposited on a second side of the substrate layer. The controllable semiconductor elements are mounted, for example, on the first metallization layer. The second metallization layer is usually attached to the base plate. When mounting the controllable semiconductor devices to the substrate, e.g., by soldering or sintering, the semiconductor devices are usually pressed onto the first metallization layer with a certain amount of force and under the influence of high temperatures, wherein the temperatures usually lie at about 300° C., sometimes even 500° C. and more. This leads to a deformation of the substrate, usually a convex deflection in the direction of the first metallization layer on which the semiconductor elements are mounted.
Base plates are usually manufactured to have a concave deflection in the direction of the surface on which the one or more substrates are to be mounted. The deflection of the base plate, therefore, is opposite to the deflection of the substrate. When mounting the substrate to the base plate, a connection layer is arranged between the base plate and the substrate. Such a connection layer usually completely fills the space between the base plate and the substrate and therefore has a non-uniform thickness because of the opposite deflections of the substrate and the base plate. The thickness of the connection layer influences the heat conduction as well as other parameters. The grade of deformation of the substrate as well as of the base plate may vary between different substrates and base plates and is usually not predictable, which may lead to unpredictable thicknesses of the connection layer and to an unpredictable thermal conduction. This may limit the reliability of the semiconductor arrangement and the whole power semiconductor module arrangement.
There is a need for a semiconductor substrate that avoids the drawbacks mentioned above as well as others and which allows to produce power semiconductor module arrangements with an increased reliability, and for an apparatus and a method for producing such a semiconductor substrate.